Alvarado’s demotion, while not expected, was warranted as the southpaw had struggled since an impressive first month following his promotion from the Double-A Montgomery Biscuits. Alvarado gave up runs in five of his last six outings while taking three losses.

Per Marc Topkin (Tampa Bay Times), the Rays didn’t have any obvious replacements, but are turning to Kolarek, who had been pitching well for them at Triple-A Durham, posting a 1.36 ERA for 33 innings over 31 games, allowing 26 hits and 12 walks with 29 strikeouts.

Kolarek spent time both in Double-A and Triple-A last season. He received a spring training invite from the Atlanta Braves, but was let go and ended up re-signing with Tampa Bay at the end of Spring Training. He initially spent time in the Mets organization, getting as far as Triple-A for two games four years ago.

When Kolarek makes his big league debut, he will become the eighth such player to do so for the Rays this season. Only the Cincinnati Reds have one more player that’s done the same.

To make room for Kolarek on the 40-man roster, the Rays moved CF Kevin Kiermaier from the 10-day to the 60-day DL.